The Experts below are selected from a list of 441294 Experts worldwide ranked by ideXlab platform
Jaco J Geuchies - One of the best experts on this subject based on the ideXlab platform.
-
in Situ Study of the formation mechanism of two dimensional superlattices from pbse nanocrystals
Nature Materials, 2016Co-Authors: Jaco J Geuchies, Carlo Van Overbeek, Wiel W Evers, Bart Goris, Annick De Backer, Anjan P Gantapara, Freddy T Rabouw, Jan Hilhorst, Joep L PetersAbstract:A real-time Study of the growth of two-dimensional nanocrystal superlattices with square periodicity shows the formation mechanism leading to the oriented attachment of the nanocrystals.
-
in Situ Study of the formation mechanism of two dimensional superlattices from pbse nanocrystals
Nature Materials, 2016Co-Authors: Jaco J Geuchies, Carlo Van Overbeek, Wiel W Evers, Bart Goris, Annick De Backer, Anjan P Gantapara, Freddy T Rabouw, Jan Hilhorst, Joep L PetersAbstract:Oriented attachment of PbSe nanocubes can result in the formation of two-dimensional (2D) superstructures with long-range nanoscale and atomic order. This questions the applicability of classic models in which the superlattice grows by first forming a nucleus, followed by sequential irreversible attachment of nanocrystals, as one misaligned attachment would disrupt the 2D order beyond repair. Here, we demonstrate the formation mechanism of 2D PbSe superstructures with square geometry by using in Situ grazing-incidence X-ray scattering (small angle and wide angle), ex Situ electron microscopy, and Monte Carlo simulations. We observed nanocrystal adsorption at the liquid/gas interface, followed by the formation of a hexagonal nanocrystal monolayer. The hexagonal geometry transforms gradually through a pseudo-hexagonal phase into a phase with square order, driven by attractive interactions between the {100} planes perpendicular to the liquid substrate, which maximize facet-to-facet overlap. The nanocrystals then attach atomically via a necking process, resulting in 2D square superlattices.
Joep L Peters - One of the best experts on this subject based on the ideXlab platform.
-
in Situ Study of the formation mechanism of two dimensional superlattices from pbse nanocrystals
Nature Materials, 2016Co-Authors: Jaco J Geuchies, Carlo Van Overbeek, Wiel W Evers, Bart Goris, Annick De Backer, Anjan P Gantapara, Freddy T Rabouw, Jan Hilhorst, Joep L PetersAbstract:A real-time Study of the growth of two-dimensional nanocrystal superlattices with square periodicity shows the formation mechanism leading to the oriented attachment of the nanocrystals.
-
in Situ Study of the formation mechanism of two dimensional superlattices from pbse nanocrystals
Nature Materials, 2016Co-Authors: Jaco J Geuchies, Carlo Van Overbeek, Wiel W Evers, Bart Goris, Annick De Backer, Anjan P Gantapara, Freddy T Rabouw, Jan Hilhorst, Joep L PetersAbstract:Oriented attachment of PbSe nanocubes can result in the formation of two-dimensional (2D) superstructures with long-range nanoscale and atomic order. This questions the applicability of classic models in which the superlattice grows by first forming a nucleus, followed by sequential irreversible attachment of nanocrystals, as one misaligned attachment would disrupt the 2D order beyond repair. Here, we demonstrate the formation mechanism of 2D PbSe superstructures with square geometry by using in Situ grazing-incidence X-ray scattering (small angle and wide angle), ex Situ electron microscopy, and Monte Carlo simulations. We observed nanocrystal adsorption at the liquid/gas interface, followed by the formation of a hexagonal nanocrystal monolayer. The hexagonal geometry transforms gradually through a pseudo-hexagonal phase into a phase with square order, driven by attractive interactions between the {100} planes perpendicular to the liquid substrate, which maximize facet-to-facet overlap. The nanocrystals then attach atomically via a necking process, resulting in 2D square superlattices.
Zhiwei Shan - One of the best experts on this subject based on the ideXlab platform.
-
in Situ Study of the initiation of hydrogen bubbles at the aluminium metal oxide interface
Nature Materials, 2015Co-Authors: Degang Xie, Zhangjie Wang, Jun Sun, Zhiwei ShanAbstract:The presence of excess hydrogen at the interface between a metal substrate and a protective oxide can cause blistering and spallation of the scale. However, it remains unclear how nanoscale bubbles manage to reach the critical size in the first place. Here, we perform in Situ environmental transmission electron microscopy experiments of the aluminium metal/oxide interface under hydrogen exposure. It is found that once the interface is weakened by hydrogen segregation, surface diffusion of Al atoms initiates the formation of faceted cavities on the metal side, driven by Wulff reconstruction. The morphology and growth rate of these cavities are highly sensitive to the crystallographic orientation of the aluminium substrate. Once the cavities grow to a critical size, the internal gas pressure can become great enough to blister the oxide layer. Our findings have implications for understanding hydrogen damage of interfaces.
-
in Situ Study of the initiation of hydrogen bubbles at the aluminium metal oxide interface
Nature Materials, 2015Co-Authors: Degang Xie, Zhangjie Wang, Jun Sun, Zhiwei ShanAbstract:Gas-filled bubbles at the interface between a metal substrate and an oxide coating can cause blistering and eventual cracking of the oxide layer. The microscale mechanisms of how hydrogen bubbles form and grow have now been elucidated.
Vladimir L Solozhenko - One of the best experts on this subject based on the ideXlab platform.
-
orthorhombic boron oxide under pressure in Situ Study by x ray diffraction and raman scattering
Journal of Applied Physics, 2016Co-Authors: Kirill A Cherednichenko, Yann Le Godec, Aleksandr Kalinko, M Mezouar, Vladimir L SolozhenkoAbstract:High-pressure phase of boron oxide, orthorhombic β-B2O3, has been studied in Situ by synchrotron X-ray diffraction to 22 GPa and Raman scattering to 46 GPa at room temperature. The bulk modulus of β-B2O3 has been found to be 169(3) GPa that is in good agreement with our ab initio calculations. Raman and IR spectra of β-B2O3 have been measured at ambient pressure; all experimentally observed bands have been attributed to the theoretically calculated ones, and the mode assignment has been performed. Based on the data on Raman shift as a function of pressure, combined with equation-of-state data, the Gruneisen parameters of all experimentally observed Raman bands have been calculated. β-B2O3 enriched by 10B isotope has been synthesized, and the effect of boron isotopic substitution on Raman spectra has been studied.
-
orthorhombic boron oxide under pressure in Situ Study by x ray diffraction and raman scattering
arXiv: Materials Science, 2016Co-Authors: Kirill A Cherednichenko, Yann Le Godec, Aleksandr Kalinko, M Mezouar, Vladimir L SolozhenkoAbstract:High-pressure phase of boron oxide, orthorhombic \b{eta}-B2O3, has been studied in Situ by synchrotron X-ray diffraction to 22 GPa and Raman scattering to 46 GPa at room temperature. The bulk modulus of \b{eta}-B2O3 has been found to be 169(3) GPa that is in good agreement with our ab initio calculations. Raman and IR spectra of \b{eta}-B2O3 have been measured at ambient pressure, all experimentally observed bands have been attributed to the theoretically calculated ones, and the mode assignment has been performed. Based on the data on Raman shift as a function of pressure, combined with equation-of-state data, the Gr\"uneisen parameters of all experimentally observed Raman bands have been calculated. \b{eta}-B2O3 enriched by 10B isotope has been synthesized, and the effect of boron isotopic substitution on Raman spectra has been studied.
Alberto Carlos Botazzo Delbem - One of the best experts on this subject based on the ideXlab platform.
-
effect of fluoride toothpaste containing nano sized sodium hexametaphosphate on enamel remineralization an in Situ Study
Caries Research, 2019Co-Authors: Marcelle Danelon, Emerson Rodrigues De ,camargo, Luhana Santos Gonzales Garcia, Juliano Pelim Pessan, Amanda Passarinho, Alberto Carlos Botazzo DelbemAbstract:OBJECTIVE To evaluate the remineralizing potential of a conventional toothpaste (1,100 ppm F) supplemented with nano-sized sodium hexametaphosphate (HMPnano) in artificial caries lesions in Situ. DESIGN This double-blinded crossed Study was performed in 4 phases of 3 days each. Twelve subjects used palatal appliances containing 4 bovine enamel blocks with artificial caries lesions. Volunteers were randomly assigned into the following treatment groups: no F/HMP/HMPnano (Placebo); 1,100 ppm F (1100F); 1100F plus 0.5% micrometric HMP (1100F/HMP) and 1100F plus 0.5% nano-sized HMP (1100F/HMPnano). Volunteers were instructed to brush their natural teeth with the palatal appliances in the mouth for 1 min (3 times/day), so that blocks were treated with natural slurries of toothpastes. After each phase, surface hardness post-remineralization (SH2), integrated recovery of subsurface hardness (ΔIHR), integrated mineral recovery (ΔIMR) and enamel F concentration were determined. Data were submitted to analysis of variance and Student-Newman-Keuls' test (p < 0.001). RESULTS Enamel surface became 42% harder when treated with 1100F/HMPnano in comparison with 1100F (p < 0.001). Treatment with 1100F/HMP and 1100F/HMPnano promoted an increase of ∼23 and ∼87%, respectively, in ΔIHR when compared to 1100F (p < 0.001). In addition, ΔIMR for the 1100F/HMPnano was ∼75 and ∼33% higher when compared to 1100F and 1100F/HMP respectively (p < 0.001). Enamel F uptake was similar among all groups except for the placebo (p < 0.001). CONCLUSION The addition of 0.5% HMPnano to a conventional fluoride toothpaste was able to promote an additional remineralizing effect of artificial caries lesions.
-
Remineralizing Potential of a Low Fluoride Toothpaste with Sodium Trimetaphosphate: An in Situ Study
Caries research, 2016Co-Authors: Eliana Mitsue Takeshita, Marcelle Danelon, Robson Frederico Cunha, Lp Castro, Alberto Carlos Botazzo DelbemAbstract:Objective: To evaluate the effect of a low-fluoride (F) toothpaste supplemented with sodium trimetaphosphate (TMP) on enamel remineralization in Situ. Design: Bovine enamel blocks were selected on the basis of their surface hardness (SH) after caries-like lesions had been induced, and randomly divided into 4 treatment groups, according to the toothpastes used: without F or TMP (placebo); 500 ppm F; 500 ppm F plus 1% TMP; and 1,100 ppm F. The Study design was blinded and crossover and performed in 4 phases of 3 days each. Eleven subjects used palatal appliances containing 4 bovine enamel blocks which were treated 3 times per day during 1 min each time, with natural slurries of saliva and toothpaste formed in the oral cavity during toothbrushing. After each phase, the percentages of surface (%SHR) and subsurface hardness recovery (%ΔKHNR) were calculated. F, calcium (Ca), and phosphorus (Pi) contents in enamel were also determined. Data were analyzed by 1-way, repeated-measures ANOVA, followed by the Student-Newman-Keuls test (p Results: Toothpaste with 500 ppm F + TMP and 1,100 ppm F showed similar %SHR and %ΔKHNR as well as enamel F, Ca, and Pi concentrations. Conclusion: The addition of TMP to a low-fluoride toothpaste promoted a similar remineralizing capacity to that of a standard (1,100 ppm F) toothpaste in Situ.
-
effect of toothpaste with nano sized trimetaphosphate on dental caries in Situ Study
Journal of Dentistry, 2015Co-Authors: Marcelle Danelon, Emerson Rodrigues De ,camargo, Juliano Pelim Pessan, Francisco Nunes De Souza Neto, Alberto Carlos Botazzo DelbemAbstract:Abstract Objectives This in Situ Study was to evaluate the remineralizing effect of a fluoride toothpaste supplemented with nano-sized sodium trimetaphosphate (TMP). Methods This blind and cross-over Study was performed in 4 phases of 3 days each. Twelve subjects used palatal appliances containing four bovine enamel blocks with artificial caries lesions. Volunteers were randomly assigned into the following treatment groups: Placebo (without F and TMP); 1100 ppm F (1100), 1100 supplemented with 3% micrometric TMP (1100 TMP) and with nano-sized TMP (1100 TMPnano). Volunteers were instructed to brush their natural teeth with the palatal appliances in the mouth during 1 min (3 times/day), so that blocks were treated with natural slurries of toothpastes. After each phase, the percentage of surface hardness recovery (%SH R ), integrated mineral recovery (IMR) and integrated differential mineral area profile (ΔIMR) in enamel lesions were calculated. F in enamel was also determined. Data were analyzed by ANOVA and Student–Newman–Keuls test. Results Enamel surface became 20% harder when treated with 1100 TMPnano in comparison with 1100 ( p p p Conclusion The addition of 3% TMPnano to a conventional toothpaste was able to promote an additional remineralizing effect of artificial caries lesions. Clinical significance Toothpaste containing 1100 ppm F associated with TMPnano showed a potential of higher remineralization to 1100 ppm F and 1100 ppm F micrometric TMP.
